• Journal of the Ergonomics Society of Korea
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• 제32권6호
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• pp.549-555
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• 2013

Objective: The purpose of this study was to compare the performance of drilling on the ceiling in three different postures (standing, standing on the ladder and supine on the height adjusted board) and the subjective responses of perceived discomfort after the drilling. Background: Overhead work has been identified as a major occupational risk factor and has been a main research subject. Method: Ten young participants drilled 20 holes at the pre-marked places on the ceiling in three different postures. The drilling duration, resting and drilling heart rate were measured. The levels of perceived discomfort at neck, shoulder, elbow, hand and overall body were asked at the end of each task. Results: The working posture affected the heart rate after the drilling. Perceived discomfort in the neck decreased significantly in supine compared to drilling on the ladder. Conclusion: The results of this study suggest that drilling in supine can be an alternative way to reduce the drilling heart rate and the level of perceived discomfort in the neck without sacrificing the productivity. Application: The results of this study would be considered when drilling on the ceiling is required in construction workers.

• Journal of the Korean Society of Clothing and Textiles
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• 제10권2호
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• pp.29-35
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• 1986

The main purpose of the study was to investigate relationships between subjective evaluation of comfort/discomfort and tactile sensation. It was also attempted to analyse physical properties of fabric, hence to find physical factors which have effects on wearing- comfort. The results were as follows; 1. Polyester fabric B Type ranked the highest on subjective comfort scale of T-shirts. 2. Scratchiness and flexural rigidity among subjective factors were important on overall comfort sensations of the subjects. 3, In winter, subjective factors, suchas Soratchiness, Heaviness & Flexural Rigidity, were significantly correlated with objective factors of Scratchiness, Thickness & Weight, Stiffness, respectively. 4. In summer, subjective factors such as warmth, Heaviness, Clammy & Cling Tension, Flexural Rigidity, were significantly correlated with objective factors of Thermal Insulation, Thickness & Weight, Cling Tension and stiffness, respertively. 5. Scratchiness, Weight, Stiffness & Thermal Insulation among objective factors were important on overall comfort sensation of the subjects.

• Journal of Korean society of Dental Hygiene
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• 제14권4호
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• pp.563-570
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• 2014

Objectives : The purpose of this study was to investigate the relationship of subjective recognition for oral health in HBsAg positive carriers based on the data of the $5^{th}$ National Health and Nutrition Examination Survey. Methods : A statistical package SPSS 21.0 was used to analyze the relationship between oral health status and subjective oral health awareness based on data of the $5^{th}$ National Health and Nutrition Examination Survey. Results : The subjective poor oral health was found in those who had mastication and speaking discomfort and those having dental prosthesis. Conclusions : The respondents considered themselves to be in poor oral health when the subjective systemic health status and objective oral health status were worse.

• IEIE Transactions on Smart Processing and Computing
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• 제2권5호
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• pp.255-265
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• 2013

3DTV is expected to be a promising next-generation broadcasting service. On the other hand, the visual discomfort/fatigue problems caused by viewing 3D videos have become an important issue. This paper proposes a perceptual quality assessment metric for a stereoscopic video (SV-PQAM). To model the SV-PQAM, this paper presents the following features: temporal variance, disparity variation in intra-frames, disparity variation in inter-frames and disparity distribution of frame boundary areas, which affect the human perception of depth and visual discomfort for stereoscopic views. The four features were combined into the SV-PQAM, which then becomes a no-reference stereoscopic video quality perception model, as an objective quality assessment metric. The proposed SV-PQAM does not require a depth map but instead uses the disparity information by a simple estimation. The model parameters were estimated based on linear regression from the mean score opinion values obtained from the subjective perception quality assessments. The experimental results showed that the proposed SV-PQAM exhibits high consistency with subjective perception quality assessment results in terms of the Pearson correlation coefficient value of 0.808, and the prediction performance exhibited good consistency with a zero outlier ratio value.

• Journal of the Ergonomics Society of Korea
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• 제22권3호
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• pp.57-73
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• 2003

Although body pressure distribution is sensitive to movements and is relatively simple to measure even in small space, there are few researches involving applications to driver's posture and its change. The main objective in this study is the application of body pressure distribution measurements for the prediction of the driver's posture and its change. This requires quantitative analyses of the dynamic body pressure distribution, which is the change of body pressure distribution with time. The experiment involved 16 male subjects who drove for 45 minutes in a seating buck. Measurement time, stature group, and lumbar support prominence were selected as independent variables, with subjective ratings of driver's discomfort, body posture data of hip, torso. knee angle, and body pressure data variables as dependent variables. The body pressure change variables and subjective ratings were found to increase as the measurement time increased and body pressure ratio variables reflected the torso angle. From the results and analysis of the body posture data and subjective rating results, it was predicted that the seats and the design of the lumbar supports used in the experiment was not fit for tall subjects, which could also be confirmed through the body pressure distribution data.

• Industrial Engineering and Management Systems
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• 제8권2호
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• pp.121-130
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• 2009

Subjective evaluation has always been regarded as a branch of social science research. Hence, in scientific and especially engineering points of view, its development is always taken for granted despite the importance of its effects on the design and development decisions. In the past, at least two automotive seat survey questionnaires have been developed with high statistical validity and reliability. Nonetheless, both were not local while subjective perception very much depends on demographic background factors. It is felt that since vehicle seat comfort is an important aspect in a seat design, a local sense should be put into the survey that is used as the subjective tool. The proposed vehicle seat discomfort survey questionnaire was developed in dual languages; English and Malay. Malay language is the national language of Malaysia, where the survey was tested. Beside inputs from literatures, key informant interviews helped in establishing the appropriate terms used as survey items. Three experimental runs on two different seats by 22 paid subjects showed that the developed questionnaire is reliable and valid. Furthermore, criterion validity analysis on the survey and previously developed survey showed significant correlation at 0.01 significance level.

• Journal of Korean Ophthalmic Optics Society
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• 제18권4호
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• pp.429-439
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• 2013

Purpose: This study was assessed to investigate the change of subjective and/or objective symptoms and the light transmissibility of lens caused by over-usage of daily disposable circle contact lenses (circle lens). Methods: Three daily disposable circle lenses made of etafilcon A, hilafilcon B, and nelfilcon A were applied on 20 normal eyes free from any eye diseases by when subjects complained any kind of discomfort. On the first and the last days of lens wearing, subjective discomfort, blinking rate, non-invasive break-up time, lens centration on corneal surface and visible light transmissibility of lens were recorded at every case and compared. Results: The circle lens wearers complained discomfort when they wore the circle lens more than 15 hours, in excess of 8 hours being the recommended wearing time and the most circle lens wearers quit the lens wearing when they wore more than 30 hours. On the last day of lens wearing, the representative subjective discomforts were stiffness, dryness and tiredness. When the subjects wore circle lens more than the recommended time, a tendency of increased blinking rate and decreased NIBUT was observed when it compared with the values right after lens wearing. On the last day of lens wearing, the lens centration was shown to be decentrated from the pupil center compared with the centration right after the wearing. These changes in lens centration and blinking rate were consistently shown in all cases of lens wearing however, the difference in the degree of subjective and/or objective change was present depending on lens materials and subjects. The visible light transmissibility of circle lens has largely been changed. Conclusions: From these results, it was thought that the decreased NIBUT induced dryness and stiffness and decreased visible light transmissibility caused more blinking when daily disposable circle lens was exceedingly used, which provoked lens decentration and subjective discomfort. However, the difference of subjective and/or objective change was largely varied in accordance with the lens material types and individuality and thus it may occur some unexpected problems by the individual base. Therefore, the education about the necessity to comply with the recommended wearing time and the problem will be essential.

• Journal of the Ergonomics Society of Korea
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• 제32권6호
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• pp.511-516
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• 2013

Objective: The objective of this study is designing an optimal hand tool through maximum grip force study accordance to the hand grip span. Background: In order to prevent musculoskeletal diseases, studies on hand tool design are proceeding based on grip strength, finger force, and contribution of individual finger force on total grip strength. However, experimental apparatus using a tool that is actually used in work place was almost non-existent. Method: 19 males were participated in an experiment. Using the load cell inserted real plier, finger force, grip strength, and subjective discomfort rate of both hands (dominant and non-dominant) were measured in 5 different hand grip span(45mm, 50mm, 60mm, 70mm, and 80mm). Results: There was significant difference(p<0.001) of total grip strength, individual finger force and subjective discomfort rating according to various hand grip span(45, 50, 60, 70, and 80mm). Also, statistically significant different(p<0.001) was shown between the dominant hand and non-dominant hand. In addition, individual finger force in maximum grip was in order of middle finger, ring finger, index finger, and little finger. Conclusion: Optimal grip span of pliers that exerting maximum grip strength is 50~60mm. Application: This finding is expected to be used for designing proper pliers.

• Journal of The Korean Society of Integrative Medicine
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• 제10권4호
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• pp.35-47
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• 2022

Purpose : As the number of patients with systemic diseases is increasing in the old, the relevance of oral health is gaining particular research interest. To provide fundamental resources for dental services, this study examined the relationship between doctors' diagnoses of circulatory diseases and patients' awareness of oral health and oral care behaviors. Methods : SPSS 26.0 was used to assess various variables, including doctor's diagnosis of circulatory diseases, gender, age, household income quintile, participation in economic activity, marital status, subjective level of oral health awareness, mastication discomfort, speaking and chewing discomfort, dental inspection, use of oral care goods, teeth brushing during the previous day, and untreated oral conditions. Results : The circulatory diseases suffered by the subjects were as follows: 56 % high blood pressure, 36 % dyslipidemia, 6 % stroke, and 8 % myocardial infarction or angina. A higher age meant a higher diagnosis rate of high blood pressure (p<.001) and stroke (p<.001). Those with dyslipidemia showed a higher rate of receiving oral inspection (p=.040), and an untreated oral condition was more frequently observed among those not diagnosed with the disease (p=.035). The subjects who were not diagnosed with stroke showed a higher rate of oral inspection (p<.001), while those who had a prior experience of stroke suffered a higher rate of mastication discomfort (p=.020). People who had high blood pressure showed a lower rate of using oral care goods (p<.001), and those diagnosed with stroke showed a lower rate of brushing teeth the previous day. Conclusion : This study found a correlation between the diagnosis of circulatory diseases and the awareness of oral health and oral care behavior. Consequently, oral health education should be included in mental health-related education, and customized training to teach teeth brushing and the use of oral care goods should be provided to patients with circulatory diseases during dentist visits.

• Journal of Preventive Medicine and Public Health
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• 제28권2호
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• pp.433-449
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• 1995

The study subjects in this study are 295 workers who work on one electronics industry, and they were composed of 93 VDT and 202 non-VDT workers. This study was carried out to obtain the prevalence of subjective symptoms and to compare psychological symptom scores from SCL-90-R between VDT and non-VDT work groups. And to verify the relationship between VDT work related symptoms and psychological symptoms, the author compared SCL-90-R T scores between symptom complaining and non-complaining groups. The results are summarized as follows : 1. Throughout the prevalence study of VDT work related symptoms according to VDT work state, the author could select the final 10 symptoms by sex;'eye fatigue', 'foggy vision', 'neck discomfort or pain', 'shoulder discomfort and pain', 'light headedness', 'dizziness', 'acne', 'itching sensation on face', 'difficulty in concentration', 'memory disturbance' in males, and 'blurred vision', 'foggy vision', 'neck discomfort or pain', 'shoulder discomfort and pain', 'abdominal distention', 'indigestion', 'acne', 'prickling sensation on face', 'difficulty in concentration', 'memory disturbance' in females. 2. Throughout comparison of psychological symptom scores from SCL-90-R between VDT and non-VDT workers, except 'Interpersonal sensitivity' in female, Mean T score were higher in VDT workers, but not significantly different between the two groups. These results indicate that the relation between VDT work status and psychological symptoms are not strongly correlated. 3. Because of the nonspecific characteristics of VDT work related symptoms, from the 40 subjective symptoms, the author selected the final 10 symptoms by sex, especially correlated to VDT, and divided the study subjects into symptom complaining and non-complaining groups. The mean SCL-90-R T scores between the two groups were compared. Except for the opthalmologic symptoms in females, the scores were significantly different between the two groups in all symptoms. And this indicates that the VDT work related symptoms strongly correlated with the present individual psychological conditions. 4. Due to understand that which of the 9 psychological symptom dimensions are strongly correlated with the subjective symptoms, the author excuted muliple logistic regression analysis, and the result were as follows; 'depression' and 'somatization', in male, and 'obsessive-compulsive' and 'somatization' in female.